Sand-blast apparatus



July 6, 1926. 1,591,667

G. C. FATSCHER I SAND BLAST APPARATUS Filed J 10, 1925 Fig I iNVENTOFi 0 7 BY HIS Al IORNEYS Patented July 6, 1926.

UNITE-D sures P ATE-N OFF-ICE GEORGE C. FA'ISCHEB, OF NEW' HAVEN, CONNECTICUT, ASSIGNOR TO THE NEW HAVEN SAND BLAST COMPANY OFQTEW HAVEN, CONNECTICOT, A CORPORATION OFCO1\T- NECTICUT.

SAND-BLAST arPAnA'rUs.

Application filed. July 10,1923. Serial 1%. 650,659.

My invention relates to sand blast apparatus, and particularly to the mixing chamber at which sand is taken up by the blast, as for instance in a sand blast hose machine. The object of my invention is to provide a mixing chamber of such construction that an even, free and welldistributed supply of sandt'o the blast is insured during the operationof the apparatus, While clogging oi the chamber by sand on halt ofthe blast is prevented. A further object of the invention is toprovide a construction in which parts most subject to wear are readily accessible for renewal.

In the accompanying drawings Fig. l-is a verticalsectionthrough a mixing chamber in which my inventionis embodied in one form; and

Fig. 2 is a section on the line 22, Fig. 1.

In certain prior constructions, such for example as that shown in the Dreisbach Patent No. 1,093,551, April 14, 19l4,'attempt has been made to provide for;the proper delivery of the sand to the blast which passes throughthe mixing chamber, andto prevent clogging of the letter when the blast 1s halted. EXPQPIQHCG has proven, howeveig that sand ls not readily taken up such as that shown in theDr'eisbaCh patent, while moist sand will not freely flow to a mixing chamberjthrough the'lateral apertin-es such as are there provided for the purpose. "Ihe present construction obviates these difliculties by insuring the delivery of the sand in suspension to the blast, and pro viding, furthermore, suitable means below the sand feed aperture which prevents the complete closure of the blast passage by the sand when the blast is halted.

In the; illustrative embodiment of my invention shown in'the accompanying draw- -inp;s,'the sand hopper or storage tank 1 delivers to the throat 2st the top of the mixing chamber casting 3. To one end of the chamber i of 'thedatter air enters by the air blast pipe 5, while fat the opposite enrl of the chamber is the outlet fitting 6 through which the entrained sand passes to the point otuse. "Ablast hose (not shown) is commonly connected to the fitting 6. Any suitable means, such as screw bolts 7, connect the fitting 6 detachably to the casting 3.

Held within the chamber 4 by the fitting the pipe v and carried along by'the blast in suspensuitable means may be provided for properly positioning the sleeve within the chamber at in order to insure registry ofthe port 9 withthe delivery throat 2 and the'horizontal position of the feed plate 10. For this purpose I have shown bosses 12 on the sleeve adapted to enterbetween guide ribs 18 on the inner wall of V the chamber 4. Studs 1% arranged at appropriate points on the inner wall otthe chamber, engage the sleeve'S and properly position the' latter. An inner shoulder 3 on the casting 3 forms an abut'ment'for one end of the tubularlin- 'ing 8, while the opposite end of the lining is engaged by themner margin'ot' the outlet fitting 6.

V lhe'liningisthus secured accuratel'y in position not only by' the bossesl2 and labels against rotation in the chamber,

7 [but also by the shoulder B andbutlet fitting by the blastfrom the bottom of a chamber 6 against longitudinal displacement.

To control the amount of sand'dehvered to'the mixing chamber, 1 prov de agate valve 15st the inner end of a slide rod 1G,

which valveworks in the throat '2 above the I port 9 in the sleeve 8. By moving the rod.

' the mixing chamber.

Vihen the apparatus is in 10p12tti011,ti1e sand passing down through thefltl'n'oat'E and pot-t9 falls into the blast entering through Such sand" as'is notpicked up sion, tals upon the 'teedf plate 10 and is propelled by the air beyond the edge of the plate, where itis delivered into that portion of the blast which passes beneath'thc 'i'e'ed'platem, and'is taken up 'a'nd"carried The inclinaalong in suspension thereby. tion of the port 9 in the direction of the air current assists the teed of the sand from the throat to the mixing chamber, since the blast flowing past the mouth of the port exerts a suction effort on the sand feed. The sand feed may be regulated or entirely cut off by operating the gate 15. Should the air blast be halted while the gate is in open position, the flow of sand into the mixing chambe continues until a cone 17 is built up, which automatically closes the port 9 and substantially chokes the upper portion of the 111lX- ingchamber, above the feed plate 10. The passageway 18 below the feed plate however, is maintained open, and upon the renewal of the blast the air flows with increased velocity through the lower passagcway 18. If the air pressure is not suflicicntto dislodge the cone 17 at once, it is gradually broken down by reason of eddy currents or the vacuum created at A by the flow of air through the lower portion 18 of the passage, and its expansion beyond the feed plate. The sand is dislodged from one face of the cone and drawn over the delivery edge of the feed plate 10. As soon as the cone is sufficiently broken down to open air passages along the sides thereof, the sweep of the blast therethrough rapidly breaks down the remainder of the cone and renews the normal operation of the apparatus. lVhile the feed plate 10 thus performs the important function of preventing the clogging of the mixing chamber, it also performs the important function of preventing the sand from falling directly across the feed chamber when the apparatus is in operation; As above stated, such sand as is not taken up by the portion of the blast which flows above the feed plate is forced along the latter and discharged in the direction of the flow of the blast to that portion of the latter which passes beneath the feed plate. The sand is distributed in a relatively thin layer, and leaves the feed plate substantially horizontally and in the direction of the flow of the blast, so that it is readily taken up and carried along in suspension by the portion of the blast which emerges from beneath the feed plate.

I have found that even moist sand will readily feed through a mixing chamber of the present construction without any tendency to clog, either at the port 9 or elsewhere, and that even when the blast is hal ed with the port open and a wet cone 18 is built up on the feed plate 10, the action of the blast breaks down the cone and renews the feed with almost as great celerity as in the case of perfectly dry sand. I have found, furthermore, that an apparatus of substantially the same dimensions, and operated with a blast of the same pressure,

takes up and delivers a far greater quantity of sand in a given time than apparatus of the type illustrated in the patent above mentioned. The efficiency of the blast is there fore greatly increased.

Various modifications in detail of construction and arrangement of parts will readily occur to those skilled in the art which nevertheless embody the features which I claim as my invention.

1. In sand blast apparatus, a mixing chamber having a readily removable lining subdivided by an independent, readily removable feed plate.

2. In sand blast apparatus, a mixing chamber having a readily removable lining subdivided by a feed plate, said lining being apertured to afford a feed port above the feed plate, said port being inclined in the direction of the flow of air through the mixing chamber.

In sand blast apparatus, a mixing chamber having a sand feed throat, a removable tubular lining arranged beneath said throat and ported for registry therewith, and fixed means for positively locating said lining in position to insure registry between said port and throat.

I. In sand blast apparatus, a mixing chamber having a sand feed throat, a removable tubular lining arranged beneath said throat and ported for registry therewith, and fixed means for positively locat ing said lining in position to insure registry between said port and throat, together with a feed plate subdividing said lining into upper and lower blast passages, said port being located to deliver sand to the upper blast passage in the lining.

5. In sand blast apparatus, a mixing chamber having a removable tubular lining ported in its upper wall to afford a sand f ed opening to the interior of the lining, in combination with an independent feed plate horizontally sub-dividing the interior of the tubular lining and removable therefrom by displacement in the direction of the length of the tubular lining.

6.111 sand blast apparatus, a mixing chamber, abutments of less diameter than the chamber at opposite ends thereof, a tubular lining for the chamber engaged between said abutments and having an opening in its upper wall to form a sand feed port, together with a feed plate horizontally sub-dividing said lining.

In testimony whereof I have signed my name to this specification.

GEORGE C. FATSCHER. 

